Internal combustion engine



y 9, 1936. H. E. BLOMGREN 2,041,319

INTERNAL CQMBUSTION ENGINE Fil ed 00t. 22, 1932 4 Sheets-Sheet 1INVENTOR ATTORNEY May 19, 1936-.

H. E. BLOMGREN INTERNAL COMBUSTION ENGINE Filed Oct. 22, 1932 4Sheets-Sheet 2 ATTORNEY6 May 19, 1936. H. E. BLOMGREN INTERNALCOMBUSTION ENGINE 4 Sheets-Sheet. 5

Filed 061:.- 22, 1932 INVENT OR I :5 W

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' ATTORNEYS y 1936- H. E. BLOMGREN ,041,319

INTERNAL COMBUSTION ENGINE Filed Oct. 22, 1932 4 Sheets-Sheet 4 I FIRINGE fivv ENVENTOR ma ATTORNEY-S Patented May 19, 1936 UNITED STATESINTERNAL COMBUSTION ENGINE Henry E. Blomgren, Central Park, N. Y.,assignor of one-fourth to William D. McGurn, Rockville Centre, N. Y.

Application October 22, 1932, Serial No. 639,055

6 Claims.

The invention relates to and has for an object the provision of aninternal combustion engine of the expansible chamber reciprocatingpiston type that is compact, light and efficient.

The majority of engines now in use, particularly those having acomparatively large horse-power per pound ratio, are subject to greatweakening stresses. These stresses are due to many factors, notably highspeeds of operation and large centrifugal and gyroscopic forces.Particularly is this true of theradial engine with a large number ofexplosions for each revolution of the crank shaft. In addition, suchengines offer great resistance to the wind even when hooded and often 15are not adapted to be mounted in the most efficient position wherecompactness and support is a consideration as, for example, in the wingof an airplane.

In the engine of this invention, there is no 20 power crank shaft ormodification of a crank shaft, with the result that rotating stresses inthe essential power transmitting or sustaining mem-. bers arenon-existent. Instead, reciprocating members act to turn a drive shaftand the component parts of the engine are grouped in close parallelismaround this shaft; High piston speeds may be eliminated if desired byraising the ratio of revolutions per working stroke. On the other hand,where it is desired to secure maximum power by rapid succession of powerstrokes in each cylinder, with use of comparatively slow propeller speedor driven shaft speed, the motor may be operated at high speed and anextremely simple reduction effected in the transmission. Better coolingof the engine cylinders is obtained by the use of apparatus whichconducts the cooling medium around a longer path past the cylinder wallswithout increasing resistance to the fiow of the medium.

Frequent troubles are caused in engines by the valves. The end of thevalve stem wears or the rocker arm bushing wears, permitting the arm torock laterally, thus disturbing valve operation. Timing cams of thesmall heart type give a, severe blow to the rods each revolution besideswearing the rods by the continuous rubbing. My motor overcomes theseobjections.

More particularly, thisinvention discloses an engine which is propelledby a continuous twisting of proper shafts, by reciprocating devices andconsequently the enclosing chamber can be very small and compact. Too,in an embodiment to be described, weight is saved by splitting up thenumber of cylinders and also by using common 55 firing chambers. Thelast-named eliminate Several mechanisms as well. The engine cooling isdone by air, and new fins are provided having a slight twist to developmore cooling surface without adding resistance. In overhauling, thelabor is reduced to the simple unbolting of a series of sections of theengine casing. Again, in providing an engine in which the revolutionsper stroke ratio is very high, a low speed, long life motor is obtained.These elements and their functions are among the primary objects andadvantages of this invention.

Other objects and advantages and features of invention will appear fromthe description and drawings, in which Figure 1 is a top view of oneembodiment of the engine of this invention in partial longitudinalsection, showing the valve assembly in detail.

Figure 2 is a longitudinal section of the engine.

Figure 3 is an end view of the engine with the cam stroke limitingmechanism in section.

Figure 4 is a sectional view of a one-way clutch suitable for use inthis engine, taken on line 4-4 of Figure 2;

Figure 5 is a sectional view of a firing chamber in the engine.

Figure 6 is an enlarged detail view of the crank mechanism and cam shaftdriving arrangement.

, Figure '7 is a diagrammatic view of the operation of said crank.

, Figure 8 is a cross section of a rocker arm unit.

Figure 9 is a longitudinal sectional view of a modification of thisinvention.

Figure 10 is a sectional view thereof taken on line l0--l0 of Figure 9to show the timing mechanism; and

Figure 11 is a firing diagram of the engine shown in Figure 9, showingthe location of the firing chamber as viewed from the right of Figure 9.

Referring to the drawings, Ill indicates a portion of the engine casingenclosing the center of the motor and having a closure plate I l at thetop and a similar closure plate I2 below. At each end of the casing I Bthere is an integral turret l3 and M, the outer edges of which representthe extreme limits of movements of parts making an engine stroke. An endcap l5 closes the rear turret I3 and the rear of casing Ill. Bolted toturret I4 is a funnel-form extension IS, the small end of which isoutermost and serves to support the front end of a drive or propellershaft I'I. Shaft I! is a solid shaft having portions of variousdiameters which runs the whole depth of the engine into end cap IS. Asmall plate l8 sur rounds shaft H and. locks two ball bearings is and inthe end of extension l6. Just inside .the plate l8 a sleeve 2| closelyfits revolubly around shaft I1 and bears against the forward clutchassembly, to be described, there being one such at each end of themotor. Movement of the assembly forward is also prevented by an enlargedforward portion of the shaft l1 and in the other direction by aninterior flange 23 of turret I4. Similarly, in a reverse manner, therear clutch assembly is prevented from movement outward by the threadedend of the shaft I? and nuts 24. Movement of the shaft inwardly isimpossible because of a taper 25 on shaft I1 and a similar flange 26 onturret l3. Thus, from one end of the engine to the other, rigidity andresistance to reciprocating stresses is found.

Each clutch assembly, located at the outer edges of turrets l3 and [4respectively, comprises a roller thrust bearing 21 which is lockedbetween the inner edges of the cap l5 and cone i6 and the respectiveflanges 26 and 23. The bearing 21 supports a hollow cylindrical cup 28having an enlarged diameter at one end and adapted in its smallerportion to receive the tapered end of a hollow shaft 35 to be described.Nesting within the larger diameter of the cup 28 there is a ballbearing29, the inner race of which is fitted on a flange 30 of the inner memberof a one-way clutch 3|. This inner member tightly fits the shaft ill-atone clutch on taper 25 and at the other on the surface 22 of the shaftat the front end. Each center portion .3] has inclined notches 34 aroundthe outer periphery similar to those numbered 48 in Figure 4, to bedescribed. Steel rolls 32 with axes .parallel to the axis of shaft I!are placed one in each notch. Around the outside of .clutch 3| there isa cap 33 having a threaded portion engaging the outside of cup 28. Alock nut 33' is also similarly engaged, holding the cap 33.. The cap 33and cylindrical cup 28 are thus connected with shaft I! only through themedium of clutch 3| which only engages to turn shaft IT in thisembodiment in a clockwise direction when viewed from the front.

Closely fitting revolubly around the respective parts of the shaft l1,and taking up the entire distance between the two clutch assemblies 3!there are two oppositely-threaded, hollow worm shafts 35 both of thesame length whose ends are tapered at 31 respectively to fit-into thepreviously mentioned tapered openings in the bottoms of the cups 23,where they are fastened by keys 39. Lock nuts4l hold the outer ends ofshafts 35 securely in place here and constitute another fac torpreventing to and fro movement of those parts-of the engine designed tooperate without longitudinal displacement. Their inner ends 36 arethreaded for a short distance and a cup fitting 40 similar to the cup 28is screwed thereon and locked in place by a nut 42. Inside each cupfitting 40 there is a ball bearing 43, the inner race of which is fittedupon an enlarged section 44 of the drive shaft l1, maintaining aconcentric relation between the drive shaft l1 and hollow shafts 35. Aspacer ring 44 fits between the inner races of the ball bearings 43 tocomplete the shaft assembly. On each shaft 35 there is engaged a driveror nut 45 having internal worm grooves fitting the threads 46 of theworm shaft and both drivers are carried in a traveller 56 as will bedescribed. Inward movement of either driver will cause the respectiveclutch 3| to engage and turn the drive shaft I! while the other clutch31 runs free. In the engine shown, a working stroke occurs every time adriver 45 moves inwardly on its threaded shaft 35.

On each driver there is a clutch 41 the outer member of which is fixedon the follower frame 56. The clutches 41 are constructed to engage andlock the nuts 45 against counter-clockwise movement but permit freerotation of the nuts clockwise when the drivers are moved outwardlyalong the worm shafts, so that no reversal of movement of theworm-shafts or nuts is necessary.

As in Figure 4, each clutch 41 comprises an inner member secured on thedriver 45 by lock nuts 41', and. is provided with a series of inclinednotches 48 in which a series of steel rolls 49 are placed, one to anotch, tending to be propelled out upon the incline by plungers 5E! andsprings 5|. An outer member or ring 52 fits revolubly around the part41. All four clutches in this engine as described are similar to oneanother and act to engage in the same direction. Next to the clutch 4]on the nut 45 there is a roller thrust bearing 53 and a screw cap 54completes a follower assembly 55 at each driver.

The drivers .are connected together by a rigid follower frame ortraveller 56 by means of the caps 54. The frame 56 is cut away in partsto reduce weight, for ventilation, lubrication and access to partstherewithin.

At the top and bottom of the frame 56 there are formed externallongitudinal grooves 57 into which suspending or guide rails 58 arebolted. Each of these rails has a web portion 59 inserted between tracks62 and .are formed with longitudinal channels opposed to correspondinggrooves in the tracks, ball bearings 60 being interposed and held in thechannels and the grooves. Sliding retainers 6|, which hold the balls 60in spaced relation are bolted slidably to the fixed track 62 of whichthere is one on each side of each rail. The four tracks 62 are fastenedto the ends and center of the casing frame it by brackets 64 and inaddition are positioned against longitudinal movement by adjustablepositioning bolts 65.

When the follower frame 56 is at one end of its stroke and begins itsreturn, the driver at the outer end of a worm shaft 35 will immediatelybecause its respective clutch 4'! engages-begin to twist its hollowshaft 35 and through the respective clutch turn the drive shaft H assoon as the speed of the shaft 35 exceeds that of the shaft I '5. At thesame time, the clutch Si in the other clutch assembly moving outwardwill release to permit rotation of the other hollow shaft 35 to continuein a clockwise direction by previously imparted momentum, and remainsdisengaged until it in turn begins a stroke from the outer end towardthe-middle of the engine. According to the pitch of the threaded hollowshafts 35, a single stroke, instead of causing a fraction of arevolution of the drive shaft I to take place, may cause the drive shaftto be rotated one for one, two for one, or any ratio which works out inoperation.

The eight cylinders 69 for this engine as here embodied are placed insets of four at each end of the drive shaft l1 and parallel therewith inopposed relation. In turn, those at each end are in close coupled pairson opposite sides of the shaft I? and alined with respective pairs atthe opposite end of the motor. The cylinders are bolted to similar caseextension portions 7! secured to the main casing in. Arranged around theoutside of each cylinder casing 69 are the longitudinal helicoidalcooling fins 72 of slight inclination of circumferential extent, so thatincident cooling air always impinges on the fins and a greater area ofcylinder wall than would be the case if the fins intendedcircumferentially to a greater extent. The fins I2 offer extremely lowresistance to the passage of the air also.

Each set of two cylinders 69 has a common firing chamber I3 effectingtwo results: first, decreasing the weight of the engine because twosmall pistons with the same total displacement weigh less than one largepiston; and, secondly, weight is saved because the number of valvesrequired is cut in half. In an engine using a crank shaft, it isimpracticable to divide up cylinders in this manner.

In each cylinder 69 there is a piston I4 with packing rings I5 and awrist pin I6 to which is.

I hubs I9 over which the hubs" on the connecting rods I8 exactly fit.Two ball bearings 88 longitudinally spaced are provided in each hub I9,supporting a hub shaft 8| having an eccentric wrist 82 on the outer endthereof and constituting a link (as between 92 and 93 of Figure '7). Abushing 83 and a collar 84 fit around the wrist 82 and within aconcentric cylindrical flange 85 formedon the link. This collar 84 isintegral with and comprises a crank on one end of a cam shaft 86. Thecam shaft 86 projects through a ball-bearing 89 and cover plate 98,formed integrally with the case extensions II. The radius of the crank82 is the same as that of the crank collar 84 on the shaft 86. a

The diagrammatic view Figure 7 shows the fixed center of shaft 86 at 9|;92 is the center of the crank 82 and collar 84, while the center of thehubs and shaft. 8| is indicated at 93. The movement of the crank center92 around the fixed center 9| is indicated at successive stages byprimes. The dead center distance between the hub center 93 and the fixedcenter 9| will be exactly one-half of the engine stroke. Indeed, thiscrank motion in which the connected hub center 93 moves an equaldistance to both sides of the shaft center 9| is a novel way of gettinga large stroke for a small throw. This mechanism has as its additionalfunction, the absolute control of the stroke of the engine.

On one side of the engine the cam shaft 86 is continued through acamchamber 94 and extends into a position where it may be reached forpurposes of cranking and starting the engine. If, as sometimes happens,the center of hub I1 and the shaft 86 coincide, cranking by means of thecam shaft 86 might just revolve the two coinciding arms instead offorcing the hub center 93 to move back and forth. Any desired means maybe employed to initiate slight movement of the piston-connecting-rod-hubassembly, after which turning of shaft 86 will move the hub center 93with respect to the cam center 9| and the engine is started without anydifficulty. Starting of the engine may be effected by rotating the maindrive shaft II by any approved means, not

shown, there being several commercially available.

A gear 95is keyed to the cam shaft 86 next to the ball bearing 89 and ismaintained in position by a spacer 96. The shaft 86 is supported furtherout by a ball bearing 91 in a bracket from the fiange I82 and thenpasses through an oil retainer 98 to the outside. Barrel cams 99 havingfour faces I88 machined on the outside thereof are carried on drumflanges I62 with interposed cylindrical bushings I 8|. The inner edge ofeach cam 99 is provided with internal gear teeth I83, projectinginwardly beside the flange I82 and meshing with the gear 95 which iseccentrlcally placed with respect to the cam 99, in a proper relationfor positive timing, as will appear. The outer edge of each barrel cam99 bears against the respective spacer 96. Comprising the cam chamberthere is a terminal section I84 of the engine casing having an integralhead plate I85 to which the drum bearing I82 is bolted so as to extendinto the cam chamber 94. Provision is made on one side, as may be seenfrom Figure 3 to make one of the cam shafts 86 accessible for cranking.With this single exception and the extension of the drum shaft at oneend the engine is perfectly symmetrical and sealed although the shaft II may be extended at both'ends, if desired. In this eight cylinderengine there are but eight operating valves whi h are all that arenecessary for four cycle action because of the fact that there is acommon firing chamber I3 for each two cylinders 69. Each valve unit I86which is of overhead type is provided with a poppet valve head I81 ofnearly or quite the same diameter seating itself in the integralcylinder head I88. The valve has a stem I89 which extends upwardly. Aremovable sleeve guide I I8 surrounds the stem I89 in the top of thecylinder. This guide is provided with an upwardly extending circularflange III on which two concentric valve springs II2 are seated,oppositely wound to'obtain the best possible valve balance. TheseSprings 2 are retained at the upper end by a conical valve cup II3 whichfits over the end'of the valve stem I 09 and is kept in place by a.valve key I I4 slotted to engage with a reduced portion of the stem sothat the key I I4 is lockingly seated exactly in, the center of theconical cup II3.

Associated with each valve unit I86 there is a rocker arm I I5 which isfiat with the exception of the ball pivot 6. A valve casing II'I boltedto cylinder 69 has the plunger recess H8 in which there is fitted aplunger I I9 and spring I28. The

upper end of each plunger II9 serves as the un-.

der part of a bearing for the rocker arm pivot I I6. A top I2Icompletely encloses the valve mechanism and closes the valve casingII'I. Projecting through the top I2| just above the ball pivot H6 is theupper threaded end of the rocker arm guide I22 which is formed belowinto a bifurcatedbear-v ing surface I23 which fits close to the flatsides of the rocker arm 5 for a suflicient distance on each side of thepivot I I6 (see Figure 8). The rocker arm guide I22 holds screwed on itsthreaded hub I24 a cap I25 by which the top I'ZI is held in place. Thecap I25 is pierced through the middle and a set screw I2'I projectstherethrough and is locked in position by nut I28 on top of cap I 25 andnut I29 at the inner side of the cover. The lower end of the set screwI21 engages the back of an upper bearing block I38 for the rocker armball pivot I I6.- In order to vary the clearance of a presser head I3Iextending from the front end of the rocker arm H5 and overhanging thevalve key II4, all that is necessary is to change the position of theset screw I21 which will (in conjunction with spring I20) move the pivotII6 either up or down.

The rear end of each rocker arm II 5 terminates in a socket I32 in whichthe upper ball end of a push rod I33 acts. The rod I33 extendsdownwardly through an enclosing tube I34, maintained in position by acap I35 screwed to the valve casing I I1, which tube is not restrictedin its axial movement, to permit a certain amount of play and foradjustment purposes. The lower end of the rod I33 rests in-a socket I36on top of the valve tappet I31.

In this embodiment a cam roller I38 is mounted in the tappet, againstthe cam I00 in the fork of a rod I38, a threaded member I40 containingthe socket I36 being at the other end of the rod, and a tappet wall I4Isecured between the two last named. The tappet slides in a cylinder I 42bolted directly to the outside of the cover plate I05. The lower end ofthe valve rod tube I34 is located and secured inside the cylinder I42 bya cap I43. Two valve units I06 are located on each side of the engineand include an intake valve and an exhaust valve. Two cylinders I 62 aremachined in one casting. Excepting the difference in time of operation,each one of the eight valves I06 is similar to every other one. Thistype of valve mechanism ensures extremely accurate and reliableoperation over a long period of time.

In operation, a crank is applied to cam shaft 86 which extends outsidethe case and because of the gears 81 and 86, the hub of the followerframe 56 must move back and forth until the engine starts. Thereupon oneset of the pistons at one end, one-quarter of the total number, will beat the end of the compression stroke and the compressed charge will beignited, propelling the two pistons, and causing the follower 55 whichis then at the outer end of its stroke in that direction to move towardthe middle. Clutch 41 engages and causes the respective driver to twistshaft 35. This turning of one threaded shaft will cause clutch 3| in theproper clutch assembly to turn the drive shaft I1 for that stroke anumber of revolutions obtained by dividing the stroke by the pitch ofthe threads 46 on the hollow shaft 35. At the same time, the hub shaftBI and the crank 82 will cause the cam shaft 86to rotate, actuating thevalves to prepare two cylinders 69 opposite those last mentioned forfiring when the idling follower 55 comes to the end of its outwardstroke. This succession of working strokes continues, and inasmuch asthe explosions of all of the total number of cylinders occur at fourequally timed intervals, the drive is continuously positive. The factthat the drive shaft I1 will turn two or three revolutions for eachstroke provides a slow speed, long life engine.

Overhauling an engine of this type is a simple matter because of thefact that only four separate portions of the casing frame I0, two oneach side, namely H and I04, have to be unbolted and the motor will bein sections. Because of the fact, too, that there is no large crankthrow and because every reciprocating part efl'lciently fits intoposition parallel to the drive shaft I1, there is to be found in thisengine a comparatively great power output for size and weight in a fourcycle engine. With compact engines such as the one described, it is alsopossible to mount many such in tandem positions on a single drive shaftand obtain advantages thereby for certain types of work. When two suchunits are timed so that the follower frames move in opposite directionsat the same time vibration will be negligible.

In another form of the invention shown in Figures 9 through I I, thepreferred type of engine is in a sense divided through the middle andthe two portions are placed with the two end sets of cylinders head tohead with the result that the working stroke will now take place fromthe middle of the engine outward. However, the actual lines ofseparation or number of parts are not here shown. This form of theengine also assumes a more circular form in cross section. Cam means inthe new form are disposed in the center between the adjacent heads ofthe cylinders. Thus, Figures 9 and show a twelve cylinder engineconstructed according to this modification, with horizontal cylinders intwo longitudinally opposed cylinder block units or groups, six on each,with their heads toward each other. The cylinders at opposite ends arenot necessarily alined however, as illustrated in the first structure.An inspection of Figure 11 will show that for the six cylinders at eachend there are two firing chambers so that if three cylinders above ahorizontal plane have a common chamber I52 as do the three cylindersbelow at I53, then the six cylinders in the other group will have twocommon firing chambers I 50I5I on opposite sides of a vertical plane.This is done to effect the simplest timing.

In Figure 9, I50 represents a cylinder having a common firing chamberwith the cylinders I50 immediately below it, the chamber being omittedin taking the sectional view. Cylinders I52, I53 are not so connected bya common firing chamber, but may be connected to horizontally adjacentcylinders omitted in the view, by the firing chambers at 60. This isdisclosed by the firing diagram in Figure 11. A solid drive shaft I54 isprovided as in the main embodiment and is supported in the main bracketsI55. Closely fitting over the single drive shaft l54 are two oppositelythreaded hollow shafts I56, one for each half of the engine, and havinga well-known function, as before described. Followers I51 are engagedupon their respective threaded shafts I56 as in the first describedstructure. Each cylinder has a piston I58 and connecting rod I59. Eachconnecting rod is bolted at its end to a fiat annular disc I60 whichsurrounds the main shaft 554. There is one such disc I 60 for each endof the engine, and the two must be rigidly connected, in accordance withthe action of the first described structure. The inner edge of each discI60 is connected by a U-bracket I6I to the respective follower I51, andestablishes a rigid connection between cylinders and follower I51. Thecam mechanism is between the cylinder blocks and is driven directly by agear I62 keyed to drive shaft I54 and meshing with an idler gear H53 inturn engaging with the internal gear I69 on the inside of barrel camI65. This cam is supported by large ball bearings I66 mounted on oneunit of the engine, and is provided with two exterior cam faces I61 forthe entire four firing chambers I 68. Because of this fact the four setsof two valves each are spaced exactly ninety degrees from each otheraround the circumference of the engine (Fig. 10). Each valve assemblyincludes valve rod I 60 and rocker I10 and embodies all features andadvantages to be found in the valve mechanism associated with thepreferred form of engine as described.

Again, the firing is timed so that one half of the cylinders on each endfire at one time so that the main drive shaft-I54 is always beingpositively rotated. In order that all connecting rods I59 on one end ofthe engine will move back and forth in unison, the two contigious firingchambers at any end Will be engaged in complementary cyclic strokes, as,firing and intake or exhaust and compression. The six cylinders at theother end of the engine are so timed that the compression stroke oftheir pistons begins as the pistons at the first end begin to moveoutwardly. The advantages accruing to the main type of engine accrue tothis modification and the details of mechanism may be varied in manyways by skilled persons.

I claim:

1. In a motor, two longitudinally opposed sets of rectilinear cylindersall parallel to a common geometrical axis, respective reciprocatingpistons in the cylinders, a common connection between all the pistonsincluding a traveller having a lateral hub, said common connection beingpivotally connected to the hub, and a power transmitting meansoperatively connected to the traveller.

2. The structure of claim 1 a separate power transmission comprising arevolubly mounted shaft on an axis at right angles to the direction ofreciprocation of the traveller, a link pivoted on the traveller on anaxis in a plane coincident with the axis of the said shaft, and a crankof the same radius fixed on the shaft and pivotally connected at itsextremity to the extremity of the link, said link and crank having anaggregate length on centers equal to one-half the stroke of the pistons,whereby to stop the traveller and connected pistons at the limits oftheir reciprocation.

3. In a motion conversion unit for the purposes described a revolublymounted power shaft, two hollow worm shafts independently revoluble onrespective ends of the power shaft, respective unidirectional clutchescooperatively associated with each worm shaft and the power shaft toengage in the same direction whereby intermittent or oscillatory rotarymovement of the worm shafts will transmit motion in one direction to thepower shaft, a traveller reciprocable longitudinally of the power shaft,respective drivers revoluble thereon concentric with and engaged withthe threads of respective worm shafts, and respective clutches on thetraveller coactive between the drivers and traveller to engage andoppose rotation of the drivers opposite the direction of rotation of thepower shaft and to free the drivers for rotation in the same directionwith the power shaft.

4. In a crank assembly, a revoluble shaft having a fixed axis, arevoluble shaft movable transversely of its axis, means to reciprocatethe second named shaft in a path extending on two sides of the firstnamed shaft, a link element pivoted on one shaft and a crank on theother shaft, said link and crank being pivotally connected togetherhaving an aggregate length on' centers equalling the distance from saidfixed axis to the limit of reciprocation of the second named shaft.

5. In a motor of the character described, a motor frame, a multiplicityof opposed sets of cylinders all arranged symmetrically in parallelrelation to a given axis, a power shaft revolubly mounted on said axis,worm shafts revoluble on different parts of the power shaft, a travellerreciprocable parallel to the power shaft, connected drivers on the wormshafts carried by the traveller revolubly in fixed spaced relation,unidirectional clutch means between the worm shafts and power shaft andbetween the drivers and traveller, said traveller comprising a framehaving seats at respective ends, thrust and radial bearing elements ineach end of the traveller frame, a nut element revolubly carried in eachbearing and having reciprocable driving engagement with respective wormshafts, two parallel grooved guides beside the path of the travellerframe on each side, the traveller frame having complementary membersinterposed between the guides, and balls confined between the guides andcomplementary interposed members.

6. In a motor, two sets of cylinders longitudinally opposed, each setsymmetrically arranged with respect to a common geometrical axis, atrav- 'eller reciprocable on said axis, respective pistons in thecylinders, all pistons being connected to the traveller whereby allreciprocate together and simultaneously in the same direction, a powershaft revolubly mounted on said axis, two hollow worm shaftsindependently revoluble on respective portions of the power shaft,respective unidirectional clutches cooperatively associated with eachworm shaft and the power shaft, whereby intermittent rotation of theworm shafts will transmit motion in one direction to the power shaft,drivers revolubly mounted on'the traveller concentric with and indriving engagement with respective worm shafts, and respective clutcheson the traveller coactive between the traveller and drivers to opposerotation of the drivers opposite the direction of rotation of the powershaft and to free the drivers for rotation in the same direction as thepower shaft.

HENRY E. BLOMGREN.

